Automatic safety valve



A. W. LAIR AUTOMATIC SAFETY VALVE Filed July 24, 1922 INVENTOR.

Mild/ ATTORNEY.

Patented Oct. 5, 1926.

which ABRAHAM w. LAITR, on Los AN'G'E'tEs, CAL'IFO'RNI'A.

retra a r-rear; str'arc.ei;

AU'r'e'MA'ric serum? verve;

The object of the invention isto prevent the explosion of a steam boiler by making it impossible to put water in'it while under pressure or at a timewhen the "boiler is dry, or the water is dahgerously'low.* I at tain this object by the mechanismillustrated in the accempanyihg drawings;

It being known that the cause of explosion is that of putting-water in an overheated lOOllQl'5 or at a time when thewater is below the fines or tubes, or when the boiler is completely dry, at which time, and in which condition if water is permitted to enter the boiler, coming in contact with the bverheated 7 metal, it is converted into the gaseous state with eitplosive' rapidity andexplodes the boiler bythe rapid liberation of gases;

To prevent the possibility of putting water in the boiler when the water already in it is dangereusly low, I have devisedan automatic mechanism illustrated in the companying drawing which is an elevation partly in secti'omthe mechanism shown consisting of a safety valve A; andan "automane steam float chamber B, by which the valve is operated as shown in'the chewing The steam float chamber is attached to the boiler by means of a pipe 3 passing downward through a holein the boiler to the low water level. It is securely fastened by a locknut 1 around the'pip'e- I The steamfloat chamber connects withthe safety valve by means of pipes'C, which:

transmit steam from the boiler' tl'irou'gh the steam float chamber to the safety valve" when the boiler isdan'gerohsly dry 'or when thewat'er is below a safe level within'itp The safety valve is placed in the "sameposit-ion' as an ordinary globey'alve would 'be' when used to control'the steam that=op-' crates the boiler feed; (either apump or an inspirator), a globe valve beingused- 1nconnection with it is attached to the pipe-D,

valve be opened tostai't the pump or insp1r'a-' tor-thus causing an exp1osion the auto matic safety valve will prevent it, because it had already closed through the action of the nejctsthestea'm float chamber tothe boiler D D 'representsthepipe's that runfrorn the bo'iler totlie pumpor insp'i-rat'or; A globe 1922 senai No; 577,218.

valve not shown-isconnected to pipe I) and plug 8 notclosing port 14 in- -the' body, of

the valve, under which circumstance the pump 1s operated 'by means of thei'globe connected to pipe D, as in ordinary circumstances. When the water intheboilef is dangerously 10w, the-action difiers inasmuch that at such times, and under such circumstances,- the I water leaves the steam float chamber B passing back into the boiler and steam-passes up pipe 3 into steam= fidat chamber B, "this not being of-suiiicient-specific-gravity to buoy up float 4, thelatter drops downand rests" upon the pegs 23, 24,25 thus leaving port 5 open, a and then steam passes on through pipes G into the cylinder of the safety 'valve A; where it drives-piston 50, piston-headb, and plu -e forward;-closing port "'14 in the body of the" valve,- un'der which circumstancesand condition the safe- I ty valve being closedythe boiler feed; (pump or inspirator) cannotbe started.

When chamber B is filled- With water, float 4 is buoyed up -Withma force equal to the weight of the cold -water' displaced,

considering there is: no pressure on the boil er; But as the'pressure increases the'density of the waterFincreases andowing' to the-in?" creaseot density the float Will be' buoyed up still more, with afofceproportional to the densityof the water; Hence; the'fioat is buoyed" up with a force equal to the I Weight of cold water displaced, plus the density reshlting fromthe boiler pressure.

Now, given that the-mechanism is Well as- I sembled and adjustech'when the water in the boiler isof a level sufhcient to pass-tuppipe 3 into chamber B andiaise float 4; then port 22 will be closed-and no' operation of the safety valve 8 is possible; The droppingpffloat is not entirely inst-antaneoiis, =for-the Water in chamber B, being hot evolvessteam,

and as the Water'levelin :chamberB lowers by reason of its passagedown pipe-3 the space over the water level becomes 'filled'f with steam thati's evolved from the "Water in chamber B and not from the boiler, and this steam escapes through port 5 and fllls pipe 41 and the cylinder 12 of valve A, yet not sufliciently strong to operate the piston 6 in said valve, still of sufficient volume to prevent a sudden inrush of steam when the water completely drains from the pipe 3. Following this first release of steam, the float 4 drops completely down, throwing the port 22 wide open, it is then that the entire pressure from the boiler is released and passing port 22 goes to the cylinder 12 and operates the mechanism therein, hence in this action there is no sudden inrush of steam into chamber B. N ow as there is no continuous outrush of steam from chamber 13, the float 4 merely operates in a volume of confined steam which will not interfere with its action, and on the other hand it there was a continuous outrush. of steam as through an opening of pipe 41, then the inrushing steam from the boiler would blow the float 4 upwards.

There is no back pressure from the cylinder 12, for the steam passing through passage 14 is prevented from entering the cylinder when the plug 8 is pushed back into its seat 16, and if perchance a little steam did work through into the cylinder it could not enter the pipe C for it cannot pass the piston 6, the pressure only serving to hold plug 8 all the more secure in its seat 16.

The plug 8 is operated to open passage 14 after an accident has been averted by the closing of passage 14, then the plug 8 is replaced by turning the screw 17 sufliciently to loosen the plug 8, then take ofl' cylinder head 58, reach in and pull back the piston as far as it will come, reinsert cylinder head and turn back screw 17 sufliciently to allow plug 8 to again be driven into its seat across the passage 14, and the mechanism is again ready .tor another action.

Having thus made a general statement of the object and nature of the invention, with a brief description of the several views of the drawing, the following detailed description of the several parts of the mechanism will cover any omissions occurring in the preceding statements as to construction and materials out of which the invention is made. I

The invention consists generallyv of two main parts known as the body of the valve 13, and a cylinder or steam-chest 12 which is permanently attached to the body, both parts being cast together.

14 is the port or opening by which, ant through which the steam passes the valve in its circuit from boiler to pump.

8 represents a round metallic plug 'made of brass or other non-corrosive metal; it is permanently attached to piston 50, and is so constructed that it serves the double purpose of closing port 14 in the body of the ment anywhere along the piston stem 50.

6 represents a piston head made of brass or other non-corrosive metal.

11 represents a director made of brass or other non-corrosive metal; it is fitted into a socket in the body of the valve by means of screw threads; its function is that of a guide through which the piston slides forward or backward during the operation of the valve. Also within this director a depression 16 is turned which serves the purpose of a valve seat, receiving the conical shoulder 9, of plug 8, when the piston and its attached piston head 6 is moved back so as to leave port 14 in the body of the valve open. Thus, when the valve seat 16 in the director 11 is closed, the steam coming through port 14 is prevented from entering the cylinder portion otthe valve. I

58 represents the cylinder head used to close the cylinder; it has a nut 10 permanently attached to it by which it can be taken out of the cylinder as occasion requires.

17 represents a screw passing'through the body of the valve as shown in the drawing. It is not attached to plug 8, and serves only the purpose of loosening plug 8 in case it becomes wedged into the plug seat thro port 14.

In the drawing B represents that part of the invention known as the steam float chamber; it is made up of two half-cylinders 18, 19, of brass or other non-corrosive metal; the two halves being united and held together by screws 20; each half has permanently attached to it a neck 40 which receives the steam pipes 2 and 41.

lVithin the united halt-cylinders the following mechanisms are contained;

4 represents a float; it is made of thin copper or other non-corrosive metal, being merely a thin shell 29; both top, bottom and sides being of the same metal.

24 represents a valve used to close valveseat 22, when the float is buoyed up by water pressure within the cylinder; it is a part of, and is permanently attached to a carrying rod 45, which passes directly through float 4, being soldered to the metallic shell of the same both above and below.

represents a spring made of brass or other non-corrosive metal of suliicient breadth and thickness to insure its perfect'holding of float 4 in position within the cylinders; at one end it is attached to the underside of float 4 by means of a screw 26 which enters the lower end of the carrying rod 45, the other end being fastened to the floor of the lower half-cylinder by means of a screw 27, which passes through a small metallic block 28. The object of the spring being that of holding float 4 in central position within the two half cylinders or steam-chest.

21, 31, 23, 32, 25, represent metallic pegs, made of brass or other non-corrosive metal; they are screwed into the floor of the respective halves 01' the cylinder or steam-chest and are not attached to float l. Pegs 23, 32, 25, serve the purpose of a rest upon which the float settles when not being buoyed up by water within the cylinders or steam-chest, while 21 and 31, in connection with one not shown in drawing, it being behind the carrying rod 4C5, serve the purpose of directing valve 24: properly into the seat 22, by preventing float t from tilting as the water pressure drives it forward; thus assuring a perfect closing of port 5, in the neck 4-0 of the cylinder or steam-chest.

49 represents a portion of the neck of the cylinder; it projectsdownward within the upper half 18 of the cylinder or steam-chest,

being permanently cast, and turned within it, the object of which is to provide a suitable mechanism wherein the valve seat 22 is turned.

2 represents a short piece of pipe, connected to pipe 3 by means of a connection 1, all as shown in the drawing.

3 represents a straight pipe which projects downward through the boiler to the low water level; it is attached to the boiler and to the steam trap by means of the connection 1.

1 represents a pipe connector, used to connect the steam trap to the boiler substantially as shown in the drawing.

Having thus described my invention what I claim is z-- 1. In an apparatus as disclosed, a valve to be connected in a steam pipe leading from a steam boiler, a cylinder, a piston in said cylinder connected to said valve, a steam pipe leading from the boiler into said cylinder, and means for admitting steam from the boiler into said cylinder to move said piston to close said valve when the water in the boiler recedes to a dangerously low level, and a set screw for engaging said valve to dislodge it from its seat when closed.

2. In an apparatus as disclosed, a steamoperated valve to be connected in a steam pipe leading from a steam boiler, a float chamber, a steam pipe leading from the leading from said float chamber to said valve, a float in said float chamber, and a valve controlling said latter steam pipe connected to said float, to be closedby said float when raised by water in said chamber when the water in the boiler is at a safe level, and to be opened by said float when lowered by the discharge of water from said chamber, when the water in the boiler recedes to a dangerously low level, whereby steam is admitted from the boiler through said steam pipes, float chamber and said latter valve to said steam-operated valve to close the latter valve.

3. In an apparatus as disclosed, a steamoperated valve to be connected in a steam pipe leading from a steam boiler, a float chamber a steam pipe leading from the boiler to said float chamber, a steam pipe leading from said float chamber to said valve, a float in said float chamber, and a valve controlling said latter steam pipe connected to said float, to be closed by said float when raised by water in said chamber when the water in the boiler is at a safe level and to be opened by said float when lowered by the discharge of water from said chamber, when the water in the boiler recedes to a dangerously low level, whereby steam is admitted from the boiler through said steam pipes, float chamber and said latter valve to said steamoperated valve to close the latter valve, and a spring in said float chamber connected to said float for centering the float and the valve connected thereto.

4. In an apparatus as disclosed, a steam operated valve to be connected in a steam pipe leading from a steam boiler, a float chamber above the boiler, a steam pipe leading from the boiler to said float chamber, a steam pipe leading from said float chamber to said valve, a float in said float chamber,

and a valve controlling said latter steam pipe connected to said float, to be closed by said float when raised by water in said chamber when the water in the boiler is at a safe level, and to be opened by said float when lowered by the discharge of water from said chamber, when the water in the boiler recedes to a dangerously low level, whereby steam is admitted from the boiler through said steam pipes, float chamber and said latter valve to said steam-operated valve to close the latter valve, and a spring in said float chamber connected to said float for centering the float and the valve connected thereto.

ABRAHAM l/V. LAIR. 

